The present invention relates to communication network, and more particularly, to a method for distributing non-unicast routes information in a TRILL network and a corresponding RBridge.
Transparent Interconnection of Lots of Links (TRILL) is a link state algorithm based routing protocol on a Layer-2 network. A TRILL network established by using that protocol comprises Routing Bridges (RBridges) having a routes forwarding feature, each RBridge obtains the entire network topology by running an extended Intermediate System to Intermediate System Routing (IS-IS) Protocol, and computes routes information through a Short Path First (SPF) algorithm.
FIG. 2 shows an exemplary structure of a TRILL network. According to FIG. 2, its basic communication procedure is as follows: routes information computed by each RBridge through SPF algorithm constitutes a routes table to be used in forwarding packet. When a RBridge RB-A receives a packet from Host 1 and needs to forward the same to Host 2 through the TRILL network, the packet is encapsulated into a TRILL packet header, which comprises an Ingress RBridge for entering into the TRILL network, i.e., RB-A in FIG. 2, and an Egress RBridge for leaving the TRILL network, i.e., RB-C in FIG. 2, also known as destination RBridge, used for finding routes in the TRILL network. After the TRILL packet is forwarded from RB-A to RB-B according to the routes information, it is further forwarded from RB-B to RB-C according to the routes information; when it is found at RB-C that the local RBridge is the same as the Egress RBridge, then it is determined that the TRILL packet has reached the last-hop RBridge in the forwarding path, at which time the TRILL packet header needs to be stripped, and a conventional Layer-2 forwarding is executed, to eventually forward the data packet to Host 2.
During the above communication procedure, after a physical connection of the TRILL network as shown in FIG. 2 has been established, each RBridge needs to obtain link state information of the entire network to obtain the network topology, and to compute routes information through the SPF algorithm; when structure of the TRILL network changes, each RBridge needs to re-obtain network topology of the entire network, and re-compute routes information through the SPF algorithm; furthermore, even if there is no change in the network, each RBridge needs to periodically re-compute routes information through the SPF algorithm. Such computation will consume a lot of CPU resources of the RBridge, which may cause various services running at the RBridge being affected.